Bandwidth Alternatives The communications speed and capacity of telecommunications networks can be classified by bandwidth. This is the frequency range of a telecommunications channel; it determines the channel's maximum transmission rate (voiceband, medium-band, and broadband). Business Applications of Telecommunications Telecommunication applications can be grouped into the major categories of electronic collaboration systems, electronic commerce systems, and internal business systems. Cellular Phone System A radio communications technology that divides a metropolitan area into a honeycomb of cells to greatly increase the number of frequencies and thus the users that can take advantage of mobile phone service. Client/Server Networks A computing environment where end user workstations (clients) are connected to micro or mini LAN (servers) possible to mainframe (superserver). Coaxial Cable A sturdy copper or aluminum wire wrapped with spacers to insulate and protect it. Groups of coaxial cables may be bundled together in a bigger cable for ease of installation. Communications Satellites Earth satellites placed in stationary orbits above the equator that serve as relay stations for communications signals transmitted from earth stations. Electronic Collaboration The use of groupware tools and the Internet, intranets, extranets, and other computer networks to support and enhance communication, coordination, collaboration, and resource sharing among teams and workgroups in an internetworked enterprise. Electronic Commerce The buying and selling, marketing and servicing, and delivery and payment of products, services, and information over the Internet, intranets, extranets, and other networks, between an internetworked enterprise and its prospects, customers, suppliers, and other business partners. Extranets A network that links selected resources of the intranet of a company with its customers, suppliers, and other business partners, using the Internet or private networks to link the organizations' intranets. Fiber Optic Cables The technology that uses cables consisting of very thin filaments of glass fibers that can conduct the light generated by laser at frequencies that approach the speed of light. Information Superhighway A proposed national network of interconnected local, regional, and global networks that would support interactive voice, data, video, and multimedia communications. The Internet A global network of millions of business, government, educational, and research networks, computer systems, and end users. Internet Revolution The explosive growth of the Internet is the revolutionary technology phenomenon of the 1990s. The Internet has become the largest and most important network of networks today, and is evolving into the information superhighway of tomorrow. Internet Technologies The Internet and its technologies are being used to build interconnected enterprises and global networks, like intranets and extranets, that form information superhighways to support electronic collaboration, electronic commerce, and internal business applications. Internetworked Enterprise A business that uses the Internet, intranets, extranets, and other computer networks to support electronic commerce and other business processes, managerial decision making, and team and workgroup collaboration within the enterprise and among its customers, suppliers, and other business partners. Internetwork Processors Many LANs are interconnected by internetwork processors such as bridges, routers, hubs, or gateways to other LANs or wide area networks. Internetworks Internetworks enable end users to communicate with the workstations of colleagues on other LAN, or to access the computing resources and databases at other company locations or at other organizations. Interorganizational Networks Telecommunications networks that interconnect organizations with other organizations, such as businesses and their customers and suppliers. Intranetworks Internets are designed to be Internet-like open systems, whose connectivity provides easy point-and-click access by end users, and interoperability among its interconnected workstations, computers, work group, business unit, and corporate databases, and other networks. Local Area Networks (LAN) A communications network that typically connects computers, terminals, and other computerized devices within a limited physical area such as an office, building, manufacturing plant, or other work site. Modems (Modulation) A device that converts the digital signals from input/output (DEModulation) devices into appropriate frequencies at a transmission terminal and converts them back into digital signals at a receiving terminal. Multiplexer An electronic device that allows a single communications channel to carry simultaneous data transmission from many terminals. Network Architectures OSI The International Standards Organization (ISO) has developed a seven-layer Open Systems Interconnection (OSI) to serve as a standard model for network architectures in order to promote an open, simple, flexible, and efficient telecommunications environment. Network Architectures TCP/IP The Internet's protocol suite is called Transmission Control Protocol/Internet Protocol (TCP/IP). TCP/IP consists of five levels of protocols that can be related to the seven layers of the OSI architecture. TCP/IP is used by the Internet and all intranets and extranets. Network Operating System A network operating system is a program that is used to control telecommunications and the use of and sharing of network resources. Network Server LAN's use a powerful microcomputer with a large disk capacity as a file server or network server. The server handles resource sharing and telecommunications. Network Typologist Two basic types of network typologist, or structures in telecommunications networks include point-to-point lines and multidrop lines. In point-to-point lines, each terminal is connected by its own line to a computer system. In multidrop lines, several terminals share each data communications line to a computer. Open Systems Model of network protocols enabling any computer connected to a network to communicate with any other computer on the same network or a different network, regardless of the manufacturer. Protocol A set of rules and procedures for the control of communications in a communications network. Switching Alternatives In telecommunications transmission, a variety of switching alternatives exist. These include: circuit switching, message switching, packet switching, and cell switching. Telecommunications Channels Telecommunications channels are the part of a telecommunications network that connects the message source with the message receiver. It includes the physical equipment used to connect one location to another for the purpose of transmitting and receiving information. Telecommunications Media Telecommunications media are the physical media used by telecommunications channels. They include, twisted-pair wire, coaxial cables, fiber optic cables, terrestrial microwave, communications satellite, cellular, and infrared systems. Telecommunications Components Telecommunications components include terminals, telecommunications processors, telecommunications channels and media, computers, and telecommunications control software. Telecommunications Processors Multiplexers, concentrators, communications controllers, and cluster controllers that allow a communications channel to carry simultaneous data transmissions from many terminals. They may also perform error monitoring, diagnostics and correction, modulation-demodulation, data compression, data coding and decoding, message switching port. Telecommunications Software Telecommunications software includes network operating systems, telecommunications monitors, web browsers, and middleware, control and support the communications activity in a telecommunications network. Trends in Telecommunications Toward a greater number of competitive vendors, carriers, and services; toward integrated, digital, global networks for voice, data, and video, with heavy use of fiber optic lines and satellite channels; toward the pervasive use of telecommunications networks in support of business operations, managerial decision making, and strategic advantage in global markets. Virtual Private Network A secure network that uses the Internet as its main backbone network to connect the intranets of a company's different locations, or to establish extranet links between a company and its customers, suppliers, or other business partners. Wide Area Networks (WAN) A data communications network covering a large geographic area. Wireless LANs Using radio or infrared transmissions to link devices in a local area network.